Plasma cells in the spleen of the Aleutian skate, Bathyraja aleutica.

Splenic white pulp of the Aleutian skate (Bathyraja aleutica), an elasmobranch, was investigated using light and transmission electron microscopy. The major cellular constituent was plasma cells, of the typical Marshalko type, characterized by well developed rough-endoplasmic reticulum and a Golgi complex. The morphology of the rough-endoplasmic reticulum was variable, being lamellar in some cells and spherical in others. Plasma cells with distended cisternae of rough-endoplasmic reticulum and cells with Russel bodies were often observed. Only a small number of lymphocytes were encountered. These findings indicate that the splenic white pulp is the major site for immunoglobulin production in this fish, thus confirming our previous immunocytochemical observation. Globules presumably containing immunoglobulin were found consistently associated with the Golgi complex. The secretion mechanism of immunoglobulin by plasma cells is discussed in connection with the globules.